Method of and apparatus for making fine metallic powders and colloid solutions



J. SLEPLAN,

METHOD OF AND APPARATUS FOR MAKING FINE METALLIC POWD ERS AND COLLOIDSOLUTIONS.

FILED JAN. 8. 1920.

. INVENTOR dose 0%) fi/ep/tm WITNESSES: 1 2% TTORNEY Patented Jan, 2,1923,

UNHTED stares teaser PATENT @FFEGE...

JQSEPH SLEIPICAN, 0F WILKINSBURG, PENNSYLVANEA, ASSIGNOR T0WESTINGHQUSIE ELECTRIC a MANUFAGTURING CQMIPANY, A CURPOJRAliTIQN OFPENNSYLVANIA.

JSEEETHOD @F AND APPARATUS F013 MAKING FINE METALJLXG FPQWDERS ANDCOLLQID SOLUTIONS.

- Application filed January e, 19%. serial It'o. 859,187. 7

To all whom it may concern:

Be it known that I, Josnrrr SLEPIAN, a citizen of the -United States,and a resident of Wilkinsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in Methods ofand Apparatus for Making Fine Metallic Powders and Colloid Solutions, ofwhich the following is a specification.

My invention relates to methods of, and

- apparatus for, making fine metallic powders and colloid solutions,-andit has, for itsprimary object, the provision of an electrolytic processparticularly adapted to the formation of such products.

Heretofore, various methods have been practiced to obtainfine metallicpowders and colloid solutions, as, for example, by grinding or otherwisefinely dividing a metal by mechanical means. These methods have beenunsatisfactory for various reasons, among them being the fact thatcertain impurities were almost always present, because of the abrasiveaction between the metal being divided and the instrumentalitiesemployed. in treating it.

According to my present invention, I may employ a suitable metal aselectrodes in an electrolytic bath of propercharacter, and I may pass acurrent between the electrodes through the bath, reversing the directionof the flow of current at suitable intervals in such manner that themetal passing into the solution from one electrode during the flow ofcurrent in one direction is re-deposited, as

a non-adherent powder, during the flow of current in the oppositedirection.

Various modifications may be resorted to in practising my invention, andelectrodes of widely difierent characters may be employed. However, forthe sakeof clearness, Iha've illustrated in the drawings certainpreferred structures particularly adapted for the purpose. In theseveral views of the drawings, in which similar reference numeralsindicate corresponding parts, Figs. 1 and 2 are diagrammaticsectionalviews of electrolytic cells suitable, for the carrying out ofmy nvention, and Fig. 3 is a transverse sectional view of a modifiedelectrode structure.

As will be appreciated from a more careful consideration of Fig. 1 ofthe drawings, ll may provide a suitable container 1 for an elec-trol ticbath 2 in which are immersed electro es 3 and a. Supply conductors 5 and6 may lead from the electrodes to any sired to obtain, and any suitablesolution may beemployed for the electrolyte, the particular solutiondepending upon the metal constituting the electrodes. For example, 1have prepared fine powders of copper and copper colloid solutionsthrough the employment of copper electrodes immersed in an electrolyticbath of sodium chloride;

While bare metal electrodes may be employed, I pre'fen'in order toprevent concentration charges at the electrodes, caused by convectioncurrents in' the electrolyte, to

screen or cover the electrodes with a suitable covering or coating ofporous material, such as layers of cotton or asbestos tape.

For example, in Fig. 1 of the drawings, 1

have disclosed a suitable electrode construction comprising a tubularbody 8 of copper, the wall of which may be perforated, as at 9, theportion of the body immersed within the electrolyte being provided witha porous covering 10.

In practising my invention with the type of electrodes disclosed in Fig.1, a current of suitable density, which may approximate one ampere persquare inch of electrode area, is passed between the electrodes, and itsdirection of flow is reversed at suitable intervals, such as from 4 to 5seconds. these conditions, the copper passing into the electrolytic bathfrom an electrode during the flow of current'in one direction will bedeposited upon the electrode as a nonadherent powder during passage ofthe current in the opposite direction, and the resultant suspension orcolloid solution may be withdrawn from the interior of the electrode bya pipette or equivalent device from time to time. This colloid solutionmay, obviously, be treated by filtration, evaporation or equivalentmeans to obtain a fine metallic powder, if such is the product deslreWhile the electrode construction disclosed in Fig. 1 has been found tobe desirable,

other electrodes may be employed. For example, the electrodes may beBare, as indicated 'in Fig. 2, under which circumstances the metallicparticles deposited will pass directly into the main body ofvthe bathem-- ployed. In likeman'ner, if. it is inconven-.-

ployed in connection with suitable electro-j lytes Without, in any way,departing from the spirit of my invention. Furthermore, the size of thedeposited particles may be varied, within certain limits, by varying thedensity of the current. or its frequency or both. Furthermore, variousre-agents,

' which beneficially affect the colloid state,

.such'as acids, bases, protective colloids and the like, may beintroduced to the. electrolyte-at or near the electrodes to facilitateciated that m the formation of the desired fine metallic powder ordeposit.

In view of'these facts, it will be -a preinvention. is capable onumerous modi cations and, consequentl I do not wish to be, in any way,restricte ex-' cept in such respects as are ind cated in the appendedclaims.

I claim as my invention v 1. The method of forming fine metallic powdersand colloid solutions that comprises providing metallic electrodes,passing a lowfrequency current between 'sald metallic electrodesimmersed in an electrolyte. I

\ reactor;

2. The method of making fine metallic powders and colloid solutionswhich comprises providing metallic electrodes with porousscreens andpassing a low-frequency current between the electrodes while they areimmersed in an electrolyte.

3. The method of forming metallic powders and colloid solutions thatcomprisess providing metallic electrodes with a porous coverlng,lmmerslng the electrodes in an.

electrolyte,'connecting the electrodes in circu1t w1th a source ofdirect current and reversmg the ein ection of flow of the current atintervals.

' 4. The method of forming fine metallic powders and colloid solutionswhich .com-

prises providing metallic electrodes, passing a direct current betweensaidmetalhc elec-fl jj trodes immersed in an electrolyte, reversingjfiothe flow of current at intervals, fregulat ing the currentv density.

5. An apparatus for use in the. formation of metallic powders andcolloid solutions that comprises an electrolytic bath and metallicelectrodes provided with porous coverings immersed in the bath.

6. An a paratus for use in the formation of metallic powders and colloidsolutions that comprises an electrolyte, and tubular metallic electrodesimmersed therein, '-and provided with porous screens.

7. An apparatus for use 1n the forming of metallic powders and colloidsolutions that comprises; an electrolyte and electrodes immersedtherein, each electrode including a tubular perforate body of metalprovided with a porous covering.

In testimony whereof, I have hereunto subscribed my name .th's 31stday-of December 1919.

I JOSEPH SLEPIAN.

